It's mostly hard for me because of... some weird mix of biology and psychology, I guess. Since the end of highschool, I'm incapable of maintaining a "morning person" lifestyle for longer than half a week, full week at best. Nevertheless, I do appreciate the benefits of having some time alone in the office, when I can focus.
Have you done a sleep study? I used to feel this way about my own sleep schedule, turns out I sucked at breathing and sleeping at the same time (sleep apnea).
I haven't. I guess I should. You reminded me that I've been told in the past that I sometimes have moments of heavy (loud) breathing.
It's not necessarily strict; just most convenient.